Who uses GIS? There are many, many projects currently underway, in public health, government, academic institutions, commercial firms, and elsewhere.
The tools to manage these projects have been available for many years. GRASS (Geographic Resource Analysis Support System) GIS has been around since 1982. It is an oldtimer of GIS, developed by the US Army-CERL (Construction Engineering Research Laboratory). GRASS is in the public domain, as well it should be: U.S. taxpayers paid for its development, and for awhile many government agencies used it extensively.
It was supported by the US Government until about 1995, when the Government decided to out-source its GIS. The USGS (United States Geological Survey) went with ArcInfo, a full-featured GIS by ESRI (Environmental Systems Research Institute, Inc.) while others seem to have also gone to other ESRI products (e.g. ATLAS, for Census files). I think it's safe to say that ESRI is the Microsoft of the GIS world, although there are others still battling for market share (e.g. MapInfo, IDRISI).
In our course at the University of Michigan we use ESRI's ArcView, which is often called a desktop GIS system. ArcView alone is not a full-featured GIS, but combined with enough add-on modules, it basically becomes ArcInfo (and so you can do just about whatever you want your GIS to do). Desktop GIS products are popping up on so many desks that some are beginning to wonder if this is a good thing: "...as the issue of computational intensity subsides, and GIS software becomes increasingly user-friendly, more ubiquitously available, and a source for implementing spatial statistical techniques, the danger of malpractice by the non-specialist practitioner grows." Daniel Griffith, in "Practical Handbook of Spatial Statistics"[2]. (Dr. Griffith is a consultant to the GeoMed/Epid624 project.)
What do you think? Should we keep these tools out of the hands of the people because they're likely to commit malpractice with them?